These pathogenic B cell clones may lie within the double negative B cell subset (CD19+IgD‐CD27‐ cells) that, although not identified as altered at the population level in our study, have been shown to be elevated in AD patients as well as in various autoimmune disorders and infectious challenges, as well as during the normal aging process.25, 37, 38. This evidence concerns the gene CD27 and Alzheimer disease.